Lubricant containing a reaction product of water-soluble sulfonic acids and phosphorus sulfide



Patented Dec. 18, 1951 OFFICE LUBRICANT CONTAINING' A REACTION PRODUCT OF WATER-SOLUBLE SUL- FONIC ACIDS AND PHOSPHORUS SUL-' FIDE Michael W. Freeman, Detroit, Mich.

No Drawing. Application August 27, 1946, Serial No. 693,374

8 Claims. (01. 252-33) cants and methods of making the same, and more particularly to new lubricating additives soluble in water or various aqueous mediums and suitable for use in metal working operations as a coolant, lubricant, etc., and also to methods of making such additives and their utilization.

The green sulfonic acids, so-called, are obtained from acid sludges formed during the refining of petroleum distillates with sulfuric acid. When refining petroleum distillates with sulfuric acid, an oil layer containing oil-soluble sulfonates and an acid sludge layer containing watersoluble green sulfonic acids are obtained. This sludge acid is removed from the petroleum distillate and sulfonic acids and their salts are extracted from the sludge by conventional means well known in the art. In such refining of petroleum distillates with sulfuric acid, sulfo acids are produced. The term broadly includes acids found in the acid sludge and acid found in the treated oil.

The sludge acids, containing what is called in the art green sulfonic acids, are water-soluble and settle out upon dilution with water in surficient quantities to cause separation of free sulfuric acid, which is then drawn off. The sludge layer is neutralized with caustic alkali to produce the sulfonates and sulfates, which are treated with naphtha, alcohol, etc., to remove any entrained oil. The oil-free sulfonates and sulfates are then acidified with sulfuric acid causing a splitting out of the water-soluble green sulfonic acids, which are removed. These water-soluble sulfo acids are neutralized to form the sulfonates.

Among the objects of the present invention is the production of lubricating additives and aqueous lubricating media utilizing products derived from the green sulfonic acids.

Further objects include the production of aqueous lubricating mediums applicable as a machining lubricant, such as for cutting, grinding, drilling, reaming, breaching, milling, threading, hot forging, cold and hot stamping, drawing, and for the plastic cold working of metals.

Other objects include the production of noncorrosive aqueous lubricating compositions capable of forming a rust-inhibiting film on metal surfaces treated with the composition and stored for long .periods of time or shipped over long distances under conditions which normally develop corrosion.

Other objects include the production of aqueous lubricating compositions possessing extreme pressure and great film strength, and which prevent seizure, galling, and metal discoloration due to excessive heat development during metalworking operations.

Still further objects include the production of aqueous lubricating compositions which are bacteriostatic, free from unpleasant odor, easy to handle and prepare, and not harmful to the health of anyone handling or using them.

Still further ob ects include methods of pre paring the lubricating additives or lubricating base products which when admixed with water of aqueous medium produce a new and improved lubricating composition.

Still further ob ects and advantages of the present invention Wlll appear from the more detailed description set forth below, it being under stood that this more detailed description is given by way of illustration and explanation only, and not by way of limitation, since various changes therein may be made by those skilled in the art without departing from the scope and spirit of the present invention.

In accordance with the present invention, a lubricating agent or lubricating additive is produced from the so-called water-soluble green sulfonic'acids derived from petroleum refining as set forth above, by reacting such water-soluble green sulfonic acids with a phosphorous sulfide under conditions usually involving elevated reaction temperatures to produce reaction products having particular value in the production of Water-soluble lubricants and lubricating compoe sitions. The green sulfonic acids utilized are those obtained in the manner set forth above but are further treated to particularly adapt them for utilization in accordance with the present invention. In carrying out the phosphorous sulfide green sulfo acid reaction, it is desirable that thesulfo compound be anhydrous at the time of reaction with the phosphorous sulfide. if not substantially anhydrous, sulfuric and phosphoric acids form during the reaction and produce an effect on the reaction product obtained involv ing a decomposition of some of the desired .products. If desired to modify the type of products obtained, some moisture may be present in the green acids at the time of reaction butgenerally it is preferred that all moisture or water be removed from the sulfo compound before reaction with the phosphorous sulfide and consequentlyja substantially .anhydrous green sulfonic acid 'i's employed in the reaction.

For these purposes the oil-free water-soluble green sulfonic acidsare re-acidified until the pH of the composition is between about 3 to about {5.5,

solvent after re-acidification. Any sulfuric acid taken up by the solvent is neutralized with caustic soda and the solvent solution mixed with anhydrous sodium sulfate. then be subjected to evaporation until a drymass forms after evaporation of the solvent. The sulfo acids may be extracted from this mass with'a suitable solvent which is then evaporated and the product dried to an anhydrous state.

The anhydrous water-soluble green sulfonic acids which are thus obtained are reacted with a phosphorus sulfide as indicated above. Any

' suitable phosphorus sulfide may be employed,

such as phosphorus trisulfide PzSa, phosphorus heptasulfide P487, or phosphorus pentasulfide P285. The amount of phosphorus sulfide employed may vary but desirably should be from about to 40% of the phosphorus sulfide based on the weight of the sulfonic acids employed. The reaction is carried out at an elevated reaction temperature which may vary depending upon the phosphorus sulfide used. For most cases it will .not exceed about, 450 F., and preferably is between 270 and 375 F. The temperature employed should be below the decomposition temperature of the reaction and the reaction is carried on until completed which is evidenced by the cessation of the evolution of hydrogen sulfide. It has been found .that by carrying out the reaction with the phosphorus sulfide in the presence of phosphorus pentoxide, the reaction is driven to completion more rapidly and smoothly, the phosphorus pentoxide appearing to act as a catalyst. The phosphorus pentoxide may be omitted, but in such cases it has been noted that the period necessary for satisfactory completion of the reaction is longer andthe reaction does not progress as smoothly. When utilizing phosphorus pentoxide a small amount is sufficient, as for example, about 1 to 5% based on the amount and-type of phosphorus sulfide used.

The materials are reacted together at theelevated reaction temperature, desirably with constant agitation. The-reaction may be carried out in the presence of a solvent or diluent, such-asa petroleum distillate or'other suitable medium desirably having a boiling point above the reaction temperature employed.

After the reaction has been completed, the product is desirably'neutralized and for this purpose the reaction temperature is lowered or permitted to drop to about 150 to 200 F. and the reaction product neutralized. Neutralization may be efiected with any desirable compound such as the alkali metal hydroxides including those of sodium, potassium, lithium, and ammonium, or with ammonia, or with amines or alkyl or aryl amines or alkylolamines, desirably utilizing wa- The entire mixture may asvaese filtration or evaporation of the solvent and any moisture formed during the reaction may be driven off at this stage by heat.

The resulting product is a new lubricating addi-' tive, particularly valuable for aqueous lubricating mediums and may be .utilized as such or in combination with other lubricating components or adjuvants. During or after neutralization, from 5 to 25% of an amine such as an alkyl or aryl amine or an alkylolamine, the percentage being based on the weight of the product being treated, may be added because of its stabilizing effect, its value in counteracting corrosion, and its importance in accentuating a desirable phase relationship with the medium which is compounded with .it, or in effecting any combination of the above mentioned functions. In most cases,

from 5 to 25% of such an amine, for example, triethanolamine, diethylamine, monoor diamylamine, monoor di-butylamine, etc., or mixtures of such amines, may be added in order to obtain a more stable and improved product.

The neutralized phosphorus sulfide-anhydrous green acid sulfo compound may be compounded with water or aqueous mediums or any emulsifiable lubricating compound to produce lubricating agents or lubricants utilizing in the composition varying amounts of the neutralized phosphorus sulfide-green acid reaction product, as for example, from 1 to 25% by weight, and preferably from 5 to 10%.

Various other organic and inorganic materials may be incorporated with the phosphorus sulfideanhydrous green sulfo compound reaction product to enhance certain phases of lubrication. Such additives may be referred to as lubrication adjuvants. Among the desirable additives are inorganic nitrites such as those of sodium, potassium, and lithium, alkali soaps of fatty acids, rosin acids, and tall oil acids, as well as the alkali metal soaps of the sulfurized and chlorinated unsaturated fatty acids, alkali metal salts such as sodium dichromate, sodium phosphates, and polyphosphates, and ammonium molybdate; Wetting agents such as aerosol, solubilizers such as alcohols, triethanolamine oleate, and oiliness agents, such as glycerine, glycols, etc. The amounts of these lubrication adjuvants which are added Will vary depending on the properties and the nature of the composition in which they are employed, but will usually run from about 0.5 to by weight and preferably in the-range of from 1 to 25%.

The phosphorus sulfide-anhydrous green sulfo compound reaction product may be utilized in combination With various lubricating mediums as lubricants for particular purposes. Thus in machining operations, a mineral oil or other hydrocarbon fraction of desired viscosity may be added so that when the water evaporates, the oil acts as a lubricant (ina plastic state at room temperature). Where a non-staining medium is desired, as on textile machinery or parts Where oil staining is objectionable, glycerol or itsesters may be added to the reaction product.

The lubricating compositions may accordingly be in the form of solutions, suspensions, dispersions, water-in-oil emulsions, etc. depending on the medium employed, the reaction product utilized, and the conditions under which it is used. The reaction products may be compounded with mineral oil, or other hydrocarbon fractions, etc. or with aqueous emulsions, depending on the use to which the lubricating composition is to be put.

The following examplesillustrate aqueous water-soluble lubricants prepared, in accordance with the present invention, the parts being by Weight unless otherwise indicated.

Example I; Approximately 50 parts by weight of a reen acid sulfonate is re-acidified with sulfuric acid until the pH is between 3 to about 6.5. Two. layers are formed, one containing free green sulfonic acids from which any entrained water has split out. The green sulfonic acids are removed and freed from residual water by evaporation or an absorptive agent such as calciurn chloride or aluminum oxide may be added to produce an anhydrous sulfo compound.

20-40 parts by weight of the anhydrous sulfo compound is dispersed in about 100 parts of a petroleum distillate solvent or in any'other suitable medium having a' boiling point above the reaction temperature utilized; 10 20 parts by weight of phosphorus pentasulfide and from 1-2 parts by weight of phosphorus pentoxide are added and the entire mixture reacted at a temperature between about 250-375 F. until evolution of hydrogen sulfide ceases. The temperature of the reaction is then lowered to about 150-200 F. and the reaction product neutralized with an excess of from 5 to 30% triethanolamine. The solvent and impurities are removed by sedimentation, filtration, extraction, and distillation. The neutralized phosphorus-sulfide-anhydrous green acid sulfo compound may then be heated to 250 F. to drive off any entrained impurities.

The neutralized product is soluble in water and aqueous emulsions.

Example II. The reaction was carried out as set forth above under Example I to a point where the evolution of hydrogen sulfide ceases. The temperature is then lowered to about 150-200 F. and the reaction product neutralized with sodium hydroxide and then admixed with an excess of from 5 to 30% triethanolamine. The organic solvent is removed by distillation. The neutralized phosphorus sulfide-anhydrous green acid sulfo compound is then heated to about 250 F. to drive oii any entrained impurities.

This product is soluble in water and aqueous mediums and a mixture of 5 to of this base in water or aqueous medium containing soaps or inorganic nitrites produces an excellent corrosion-inhibiting and extreme pressure lubricant.

Example III. The phosphorus sulfide-anhydrous green acid sulfo compound was prepared as in Example I, except that the reaction product was neutralized with lithium hydroxide and then admixed with about 5 to 10% triethanolamine. The product was purified in the manner described in the previous example.

Approximately 5 to of this base added to water or aqueous medium produces a non-corrosive, stable metal working lubricant.

Compositions used as cutting, cooling, and drawing compounds, prepared as disclosed in the above examples in amounts, for example, between 1 to 50% in water or aqueous emulsions were used for different operations and machine cutting and drawing various metals and metal alloys. A marked increase up to 100% in tool life and an increase of machining feed and speed up to 100% have been observed. Spectacular improvements were noted in close tolerance tube and shell drawing, gear cutting, and thread grinding.

Metal surfaces machined or lubricated with an Time of Sample Amount Corrosion (Inhours) Per cent Hours 15 Reference 011 100 5 Com. oil-m-Water lubricantmn 5-10 7 Com. Water-soluble lubricant... 5-10 3 Product as prepared in Example I 5-10 45 Having thus set forth my invention, I claim: l. A lubricating composition having incorporated therein a minor amount, sufficient to impart extreme pressure and corrosion inhibiting properties of a reaction product obtained by treating'a water-soluble petroleum sulfonic acid 5 as the only essential sulfonic acid present with from 10% to 40% of phosphorus sulfide, based. on the weight of water-soluble petroleum sulionic acid, at an elevated temperature not ex-- ceeding 450 F. until cessation of formation of hydrogen sulfide.

2. A mineral oil having incorporated therein a minor amount, sufficient to impart extreme pressure and corrosion inhibiting properties of a re-- action product obtained by treating a water-soluble petroleum sulfonic acid as the only essential sulfonic acid present with from 10% to of phosphorus sulfide, based on the weight of watersoluble petroleum sulfonic acid, at an elevated temperature not exceeding 450 F. until cessation 40 of formation of hydrogen sulfide.

3. A water-soluble lubricating composition having incorporated therein a minor amount, sufiicient to impart extreme pressure and corrosive inhibiting properties of a reaction product obtained by treating a water-soluble petroleum sulfonic acid as the only essential sulfonic acid present with from 10% to 40% of phosphorus sulfide, based on the weight of water-soluble petroleum sulfonic acid, at an elevated temperature not exceeding 450 F. until cessation of formation of hydrogen sulfide.

4. A lubricating composition having incorporated therein a minor amount, suificient to impart extreme pressure and corrosion inhibiting properties of a salt of a reaction product obtained by treating a water-soluble petroleum sulfonic acid as the only essential sulfonic acid present with from 10% to 40% of phosphorus sulfide, based on the weight of water-soluble petroleum sulfonic acid, at an elevated temperature not exceeding 450 F. until cessation of formation of hydrogen sulfide.

5. A lubricating composition having incorporated therein a minor amount, sufficient to impart extreme pressure and corrosion inhibiting properties of triethanolamine salt of a reaction product obtained by treating a water-soluble petroleum sulfonic acid as the only essential sulfonic acid present with from 10% to 40% of P285 at an elevated temperature not exceeding 450 F.

6. A lubricating composition having incorporated therein a minor amount, sufiicient to impart extreme pressure and corrosion inhibiting properties of a reaction product obtained by treating a water-soluble petroleum sulfonic acid 7 as; the only essential sulfonic acid present: with tram. 10%.- to 40% of Passv at an elevated ternperature not exceeding: 450 F. until: cessation of formation of hydrogen sulfide.

'Im A lubricating composition having incorporated therein from 1% to 25% of a reaction prod net ob aine it t eating water-soluble p troleum sulionic acid as the only essential sulfonic. acid p ese t h fr m 5 o 4W0 f P285 at; 311K619. vated temperature not exceeding 450 F. until cessation of formation of hydrogen sulfide.

8; A lubricating composition having incorporated therein from 1% to 25% of triethanolamine salt of a reaction product obtained by treating a water-soluble petroleum sulfonic acid as-the only essential sulfonic acid present with from 10% to 40% OfPzSs at an elevated temperature not exceeding 450 F. until cessation of formation of hydrogen sulfide. IVIICHAEL W. FREEMAN.

REFERENCES CITED The following references are of record in tfie file of this patent: v

SIATES PATENTS Number: Name Date 1,781,607 Stam'berg Nov. 11,- 1930 1195x191 Johnson May 10', 1931 2,350,959 Cook June 6. 1944 2,48 ,230 Fischer ,q, Sept. 27, 1949 OTHER REFERENES 

1. A LUBRICATING COMPOSITION HAVING INCORPORATED THEREIN A MINOR AMOUNT, SUFFICIENT TO IMPART EXTREME PRESSURE AND CORROSION INHIBITING PROPERTIES OF A REACTION PRODUCT OBTAINED BY TREATING A WATER-SOLUBLE PETROLEUM SULFONIC ACID AS THE ONLY ESSENTIAL SULFONIC ACID PRESENT WITH FROM 10% TO 40% OF PHOSPHORUS PETROLEUM SULON THE WEIGHT OF WATER-SOLUBLE PETROLEUM SULFONIC ACID, AT AN ELEVATED TEMPERATURE NOT EXCEEDING 450* F. UNTIL CESSATION OF FORMATION OF HYDROGEN SULFIDE. 